Heat Exchanger

ABSTRACT

A heat exchanger for the heat exchange between a first fluid and a second fluid, which achieves an unusual strength comprises a plurality of casings ( 2 ), of substantially flattened shape and of predetermined width (L), arranged in a pile ( 2   a ), with an air space ( 3 ) defined between adjacent casings in the pile, and each formed from two half-shells ( 6 ) welded along a peripheral strip ( 6   a ), said casings ( 2 ) being in fluid communication with each other through respective holes ( 7 ) opening into said air space ( 3 ), and at least one spacer ( 8 ), substantially of the sleeve type, in said air space ( 3 ), made integral at the top end with said adjacent casings around the respective holes ( 7 ) opening into said air space ( 3 ).

FIELD OF APPLICATION

The present invention, in its most general aspect, refers to a heatexchanger for the heat exchange between a first and a second fluid.

Particularly, but not exclusively, the invention concerns a heatexchanger for the heat exchange between pressurized fluids, of the typecomprising a plurality of casings, of substantially flattened shape andof predetermined width, arranged in a pile, with an air space definedbetween adjacent casings in the pile, and each formed from twohalf-shells welded along a peripheral strip, which are in fluidcommunication with each other through respective holes opening into saidair space.

PRIOR ART

Heat exchanger for the heat exchange between two fluids of the typecomprising a plurality of casings or flattened tubes are known.

Each casing is formed from two half-shells on which respective holes areopen, in corresponding positions, at which adjacent casings are joinedthrough collectors.

In such an arrangement, each pair of adjacent casings defines an airspace through which a first flow of fluid is conveyed, whereas a secondflow of fluid at a different temperature crosses the plurality ofcasings.

In this way, such flows carry out a heat exchange, which is generallymade more effective by making their motion highly turbulent through theuse of small corrugated plates, or turbulators, arranged in the cavitiesand inside the casings, respectively.

The aforementioned joining collectors between adjacent casings are,according to the prior art, pieces of tubes interfacing with thehalf-shells and forced, through plastic deformation, around respectiveconical edges foreseen at the holes open on the casings.

Heat exchangers thus realized, although advantageous, are not free fromdrawbacks, including the main one represented by the low mechanicalresistance that they possess and that impairs its use, in particular inthe case of heat exchange between flows of fluids at high pressurevalues.

Such a low mechanical resistance is substantial both at the jointsbetween adjacent casings, where the plastic deformation does not ensurean adequate seal, and at the half-shells which, for an effective heatexchange between the fluids, must be realized with a small thickness.

It follows from this that heat exchangers thus realized cannot be used,or in any case are of little industrial interest, in the case of heatexchange between flows of fluids of which at least one is at a highpressure value; where by high pressure value we mean a value greaterthan 10-13 bar.

SUMMARY OF THE INVENTION

The technical problem forming the basis of the present invention is thatof devising a heat exchanger for the heat exchange between a first fluidand a second fluid, of the type comprising a plurality of casings, ofsubstantially flattened shape and of predetermined width, arranged in apile, with an air space defined between adjacent casings in the pile,and each formed from two half-shells welded along a peripheral strip, inwhich the aforementioned casings are in fluid communication with eachother through respective holes opening into the aforementioned airspace, having structural and functional characteristics such as toovercome the aforementioned drawbacks, in other words such as to ensurean unusual strength and mechanical resistance.

The aforementioned problem is solved according to the invention by aheat exchanger of the type considered above, comprising, in theaforementioned air space, at least one spacer, substantially of thesleeve type, abutting on at the top end and made integral with saidadjacent casings around the respective holes opening into said airspace.

Advantageously, the heat exchanger comprises irregularities associatedwith the aforementioned at least one spacer, which extend in the airspace to rigidify the half-shells.

Preferably, the aforementioned irregularities are radial spokesextending radially from said at least one spacer.

Advantageously, the aforementioned radial spokes are practically equallyangularly spaced.

Again preferably, the aforementioned radial spokes are formed integrallywith the spacer, and more preferably radial spokes and spacer are apiece of an extruded profile.

Advantageously, the aforementioned extruded profile is made frommetallic material selected from the group comprising aluminium,aluminium alloys, copper, copper alloys and similar metallic materials.

The characteristics and further advantages of a heat exchanger accordingto the present invention shall become clearer from the description, madehereafter, with reference to the attached drawings given for indicatingand not limiting purposes.

BRIEF DESCRIPTION OF THE DRAWINGS

In such drawings:

FIG. 1 shows a schematic front section view of a heat exchanger inaccordance with the present invention, made along the line I-I;

FIG. 2 shows a plan view of the heat exchanger of FIG. 1, made accordingto the arrow II;

FIG. 3 shows an enlarged view of a detail of the exchanger of FIG. 1;

FIG. 4 shows a section view of a detail of the heat exchanger of FIG. 1,made according to the line IV-IV of FIG. 3;

FIG. 5 shows a perspective, exploded view of a portion of the exchangerof FIG. 1;

FIG. 6 shows the portion of FIG. 5 of the heat exchanger in accordancewith a variant embodiment of the invention;

FIG. 7 shows a detail of the portion of FIG. 5 in accordance with afurther variant embodiment of the invention;

FIG. 8 shows the detail of FIG. 4 in accordance with a further variantembodiment of the invention.

DETAILED DESCRIPTION

With reference to the aforementioned figures, a heat exchanger for theheat exchange between a first fluid, for example oil, and a secondfluid, for example air, realized according to the present invention, isglobally and schematically represented with 1.

The heat exchanger 1 essentially comprises a plurality of casings 2, ofsubstantially flattened shape, associated together in a predetermineddistanced relationship in a pile 2 a, with respective cavities 3 definedbetween casings.

The casings 2, of predetermined width L, are clamped, in a known way,between a first plate 4 and a second plate 5, the latter provided withjoints 5 a for the passage, for example, of the first of theaforementioned fluids.

In the example, the described exchanger has joints 5 a of 1″ (one inch).

Each of the casings 2 is formed from two half-shells 6 welded along aperipheral strip 6 a each of which is equipped, in correspondingpositions, with respective holes 7.

It should be noted that the aforementioned peripheral strip 6 a has anouter edge 6 b comprising a trim 6 c bent square, and that thehalf-shells 6 are realized in aluminium sheet of small thickness ofbetween 0.1 and 0.4 mm, preferably 0.3 mm.

Such respective holes 7, which in the pile 2 a are aligned, place theaforementioned casings 2 in fluid communication with each other.

In such casings 2, a flow of the aforementioned first fluid is made toflow, whereas the second fluid is made to flow in the aforementionedcavities 3, all in a per se known way.

In accordance with a first characteristic of the invention, the heatexchanger 1 comprises, in each of said cavities 3, a spacer 8,substantially of the sleeve type, abutting on at the top end and madeintegral with the aforementioned adjacent casings around each of therespective holes 7 of the half-shells 6, realizing an inviolablemechanical connection between adjacent casings.

Such spacers 8 made integral with the casings 2, for example throughbrazing or welding, define, at the respective holes 7, passagecollectors for the aforementioned first fluid, communicating with theinside of the casings 2.

In accordance with a second characteristic of the invention, the heatexchanger 1 comprises irregularities 9 associated with each spacer 8,which extend in each air space 3, constituting rigidifying elements ofthe half-shells 6.

With particular reference to the example of FIGS. 4 and 5, it should benoted how such irregularities are in the form of radial spokes 9,projecting radially towards the outside of said spacer 8 and practicallyequally angularly spaced on such a spacer 8.

Advantageously and in accordance with a further characteristic of theinvention, a predetermined number of such radial spokes 9 extendingoutside of the spacer 8, in the example a number equal to seven spokesindicated with 9 a, extends up to the aforementioned peripheral strip 6a.

In particular, such a predetermined number of radial spokes 9 a extendsup to, and abuts upon, the aforementioned trim 6 c bent square.

Again advantageously, the remaining radial spokes 9 of the same spacer8, in the example three spokes indicated with 9 b, are sheared accordingto a transversal plane, indicated with T, which constitutes the plane ofreference and support for a corrugated plate, globally indicated with11, arranged in each of the cavities 3 and called “turbulator” by theman skilled in the art.

Regarding this, it should also be stated that a second corrugated plateor turbulator 11 a is arranged inside each casing 2.

The aforementioned corrugated plates 11, 11 a have the purpose ofincreasing the efficiency of the heat exchange of the heat exchanger 1,increasing the turbulence, by means of their corrugated surfaces, of theflows of fluids intended for the heat exchange.

Preferably, the aforementioned radial spokes 9 are formed integrallywith the spacer 8 from which they project, and more preferably radialspokes and spacer are a piece of an extruded profile made from ametallic material selected from the group comprising aluminium, copper,aluminium alloys, copper alloys and similar metallic materials.

It should be noted that the thickness s of the spacer 8 and thethicknesses of the radial spokes 9 have values of between 2 and 4 mm,preferably 3.5 mm.

Again preferably, each of the aforementioned respective holes 7 of eachhalf-shell 6 is foreseen equipped with a centring edge 12, projectingfrom the half-shell 6 in the direction of the air space 3, for thealignment of the spacer 8.

The main advantage of the heat exchanger according to the presentinvention lies in its unusual strength.

Indeed, thanks to the spacers welded and made integral at the top end onthe casings, a particularly strong structure is given to the pile ofcasings themselves.

In this way, an inviolable mechanical connection is realized betweenadjacent casings, forming a seal and capable of withstanding violentstresses.

In particular, the portions of exchanger that according to the prior artwere most subject to explosion are reinforced, in the exchangeraccording to the invention, both through the spacers made integral withthe casings and through the radial spokes projecting from each spacerwhich constitute rigidifying elements for each of the half-shells.

The heat exchanger according to the invention, in this way, isparticularly suitable for the heat exchange between pressurized flows offluids, also for pressures of up to 35 bar and more.

Furthermore, the mechanical resistance of the exchanger is improved bythe radial spokes of the spacers, which constitute support elements foreach corrugated plate arranged in the cavities.

In this way, the corrugated plates are stably locked by the radialspokes in an optimal position that allows an excellent increase inturbulence of the flow of fluid that crosses the cavities, and anoptimal heat exchange in particular at high pressure values of such aflow.

In other words, the heat exchanger according to the present inventionallows a heat exchange to be carried out between a first fluid conveyedinside the casings, and a second fluid conveyed into the cavitiesbetween adjacent casings, in particular and at most when both of therespective flows of such fluids are at high pressure values, thanks tothe special structure described above.

Such an unusual strength of the heat exchanger according to theinvention is achieved, advantageously, simultaneously maintaining acompact structure of the exchanger, through half-shells realized with alow thickness as required for an effective heat exchange.

A further advantage achieved by the heat exchanger according to theinvention lies in the minimal or negligible pressure drop that thefluids undergo during the heat exchange, thanks to the aforementionedmechanical connection that ensures a better seal than that which hasbeen provided up to now by the prior art.

It should be stated, furthermore, that radial spokes extending up to thetrim of the peripheral strip, advantageously bent square, give the heatexchanger according to the invention an effective mechanical resistancealso against accidental knocks, preserving the heat exchanger from dentsand similar undesired damage that could derive from such knocks.

Now, with particular reference to the example of FIG. 6, a variantembodiment of the present invention is described for which details andcooperating parts having the same structure and operation as theprevious example embodiment shall be indicated with the same referencenumerals and symbols.

In such a variant embodiment, the heat exchanger comprises spacers 8,substantially shaped like a sleeve, made integral at the top end onadjacent casings 2 and comprising radial spokes 90 projecting towardsthe inside of the spacer 8.

The aforementioned radial spokes 90 projecting towards the inside of thespacer are sheared, at their free ends, so as to surround the centringedge 12 of the respective holes 7.

Again with reference to the example of FIG. 6, it should be noted thatthe spacer 8 comprises a first portion 80 a with a curved profile, and asecond portion 80 b with a squared profile constituting the referenceplane for the turbulator 11.

In such a variant embodiment it should be noted that, advantageously,the pressure that from the inside acts upon the spacer, due to the fluidthat crosses the casings, is completely counterbalanced by a pressurethat acts from the outside on the spacer, due to the fluid that crossesthe cavities.

In the example of FIG. 7 a further variant embodiment of the heatexchanger in accordance with the invention is represented.

In such a variant embodiment the heat exchanger comprises spacers 8,substantially shaped like a sleeve, each equipped with radial spokesprojecting towards the inside of the spacer, indicated with 90 a, andradial spokes projecting towards the outside of the spacer and indicatedwith 90 b.

It can be seen that the aforementioned radial spokes 90 b extendingtowards the outside of the spacer 8 are in prolongation of the radialspokes 90 a extending towards the inside of the spacer.

It is important to note that, in accordance with a further variantembodiment shown with reference to the example of FIG. 8, the holes 7open on the half-shells 6 of the casings 2 are oblong.

Holes extending transversally are particularly advantageous in the caseof large widths of the exchanger, foreseen to withstand high flow ratesof the fluid circulating in the half-shells of the exchanger itself.

The man skilled in the art can bring numerous modifications to each ofthe four variant embodiments of the heat exchanger described above inorder to satisfy contingent and specific requirements, all of thesemodifications in any case being covered by the scope of protection ofthe invention, as defined by the claims listed hereafter.

1. Heat exchanger for the heat exchange between a first fluid and asecond fluid, of the type comprising a plurality of casings (2), ofsubstantially flattened shape and of predetermined width (L), arrangedin a pile (2 a), with an air space (3) defined between adjacent casingsin the pile, and each formed from two half-shells (6) welded along aperipheral strip (6 a), said casings (2) being in fluid communicationwith each other through respective holes (7) opening into said air space(3), characterized in that it comprises, in said air space (3), at leastone spacer (8), substantially of the sleeve type, made integral at thetop end with said adjacent casings (2) around the respective holes (7)opening into said air space (3).
 2. Heat exchanger according to claim 1,characterized in that it comprises irregularities (9) associated withsaid at least one spacer (8), said irregularities (9) extending in saidair space (3) to rigidify the half-shells (6).
 3. Heat exchangeraccording to claim 2, characterized in that said irregularities (9) areradial spokes (9 a, 9 b, 90, 90 a, 90 b) extending radially from said atleast one spacer (8).
 4. Heat exchanger according to claim 3,characterized in that said radial spokes (9 a, 9 b, 90 b) extendoutwards.
 5. Heat exchanger according to claim 3, characterized in thatsaid radial spokes (9 o, 90 a) extend inwards.
 6. Heat exchangeraccording to claim 3, characterized in that said radial spokes areradial spokes extending outwards (90 b) and radial spokes extendinginwards (90 a).
 7. Heat exchanger according to claim 6, characterized inthat said radial spokes extending outwards (90 b) are in prolongation ofsaid radial spokes extending inwards (90 a).
 8. Heat exchanger accordingto claim 4 or 6, characterized in that a predetermined number of saidradial spokes (9 a) extending towards the outside of said at least onespacer (8) extends at least up to said peripheral strip (6 a).
 9. Heatexchanger according to claim 8, characterized in that each half-shell(6) comprises, at an outer edge (6 b) of said peripheral strip (6 a), atrim (6 c) bent square, and in that said predetermined number of radialspokes (9 a) extending on the outside extends up to said trim (6 c). 10.Heat exchanger according to claim 2, characterized in that saidirregularities (9) are formed integrally with said at least one spacer(8).
 11. Heat exchanger according to any one of claims 2 to 10,characterized in that said at least one spacer (8) and saidirregularities (9) are a piece of an extruded profile.
 12. Heatexchanger according to claim 11, characterized in that said piece ofextruded profile is made from a metallic material selected from thegroup comprising aluminium, aluminium alloys, copper, copper alloys andsimilar metallic materials.
 13. Heat exchanger according to claim 3,characterized in that said radial spokes (9 a, 9 b, 90, 90 a, 90 b) arepractically equally angularly spaced.
 14. Heat exchanger according toclaim 3, characterized in that a predetermined number of said radialspokes (9 b) are sheared according to a plane (T) constituting thereference and support plane for a corrugated plate (11) arranged in saidair space (3).
 15. Heat exchanger according to any one of the previousclaims, characterized in that at least one of said respective holes (7)opening into said air space (3) is equipped with a centring edge (12)for said at least one spacer (8).
 16. Heat exchanger according to anyone of the previous claims, characterized in that said respective holes(7) are oblong in a predetermined direction.
 17. Heat exchangeraccording to claim 16, characterized in that said respective holes (7)are oblong in the direction of the width (L) of said casings (2). 18.Heat exchanger according to any one of the previous claims,characterized in that said at least one spacer (8) has a predeterminedthickness of between 2 and 4 mm, preferably 3.5 mm.